1176 REV A on ebay - UNIQUE MOD??!

[Aleguitarpro]

The man in this auction boasts the unique characteristics of this mod.

http://www.ebay.com/itm/Urei-Universal-Audio-1176-REV-B-BLUESTRIPE-vintage-limiter-compressor-UNIQUE-MOD-/190966205069

The thing that puzzles me a bit is the presence of a single switch on the back that can change the mode between "stock" and the "mod".
Of course the mod may take any complex artifice and also operate a very complex switching system with relais or I do not know what, but I think it's more a lot easier and I think it is more a publicity stunt to sell before the compressor.
He states that relates to second harmonic distortion ... any idea?

 

[keefaz]

Maybe the mod switches a shunt resistor at the amp output that loads it heavily 

 

[abechap024]

Isn't there a trim pot that changes the second harmonic distortion?? Maybe it just shunts it...

Or one of the gain stages has a "bad" resistor that makes it clip asymmetrically.

I wouldn't worry about it really. Sounds like more of a marketing ploy than a silver bullet.

 

[okgb]

the soundskulpter  [ great products btw ] 1176 type has a switch that - I believe- re-bias's one of the fets to
increase the harmonic distortion ,  A friend for whom I built it for who also owns the smart C2 comp says it's
more subtle than the smart comp  [ but satisfying and usable ]

 

[joaquins]

I don't think it has anything complex inside, he even sais that's "subtle wiring change"
I'd go for the feedback trimmer shunted or changed, there are other options, load the output to gnd DC coupled, take out or move the point at the fet compensation network, etc.

Any of them could be tried out and choose the favorite, or leave a switch with all the mods, a nice rotary with 4 or 5 modes may be nice... but on the front, what's that you have to go to the back pannel to adjust something so noticeable that you may want or not in your voice! front panel pleeease!

He really wish to keep all his units but you know, he needs to sell it... 4k for a TG12413 clone seems little too much, doesn't?

JS

 

[SSLtech]

It's much easier than that. -You're all over-thinking it.

Years ago I built a couple of 'bloo' clones, and they worked well... but they sounded unusually 'hairy'.

Here's the story: http://groupdiy.com/index.php?topic=38652.0

People liked the mod SO much that they really -REALLY- didn't want me to take them apart to see what was 'wrong' in case I 'fixed' the problem... So I built the third one, using -as far as I could remember- the same parts as the first two.

...and it DIDN'T have the 'funk'. -It was a proper, normal, fully-functioning 1176.

So I dug in with a scope, probed around, and after some head scratching I noticed that the class-A output stage was being differently-biased. -It wasn't running as efficiently as it should (not that it was ever very efficient!) and ran physically hotter, but in such a manner that the onset of distortion was actually rather pleasant... and-crucially- the RECOVERY from overload was also very nice.

-So I added a switch to the back panel, and sent it out for testing. -When Morrisound Studios down in Tampa had all of their outboard gear stolen (along with their SSL G-series power supply rack and computer, etc) I lent it -along with all of my other outboard gear- to them so they could continue working. -I told them about the switch, since they do a lot of rock work.

When I collected the units back from them several months later, it seems that they had just left it mostly in the 'hairy' position, and used it for the color.

I'll keep it to myself for now... but it's way easier than most of you are thinking. -I think that more people will LISTEN and UNDERSTAND if they try things for themselves... -if they just 'paint by numbers' the change, they don't really THINK or get deep into understanding how and why things work the way that they do.

But it was a single component swap. (And it had nothing to do with the 'wrong value resistor in the reissue' problem which John Hinson pointed out several years ago.)

I had almost exactly this same 'toggle switch on the back'...

(Or you could just have someone ask Chris Lord Alge.)

Keef

 

[okgb]

I'll see if JP at skulpter can comment ,
nice to see you back Keith [ you're on the mend , have a bit of spare time ? ]

 

[JPK]

A FET transistor, when used as a voltage controlled attenuator, produces a lot of distortion, mainly second harmonic. It is very clearly explained in this application note from Siliconix:
http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/transistors/vishay_fet_cvr_an.pdf

Injecting a portion of the input signal to the control gate reduces the distortion by linearizing the bias lines of the FET around Vgs = 0.
This is what the trimmer R86 does in the 1176 REV C.
In our CP5176, the Distortion button unbalances this setting and that creates distortion, clearly visible on a triangle signal.

Now, it is not possible to deduct what is the action of the toggle switch in this ebay auction. It could be what the other people said, a change in the output stage bias, a load on the output, or a wonky distortion setting ?

 

[3nity]

Of all the 1176s ive heard the most versatile and and beautiful sounding ones is the Eddie Ciletti  clone.
It has a nice vibe and neve sounding 1176!

 

[Winetree]

WOW, $9,000.00 added value for a   
"subtle wiring change"
I'm in the wrong business.

 

[Kingston]

Not sure if you guys are considering a very real alternative that this is a complete fake unit. It's not beyond the skill set of some people - like me for example (!!) -  to completely fabricate a "rare" unit like this including the serial stickers and wear. Elaborate background stories and small deviations like the mentioned mod or that "extra switch" are the hallmark of art forgery. Meant to distract the buyer from things that might be a bit off place. I'm surprised they didn't mention the usual Arabic/Chinese/Philippine prince etc. European royalty that was the previous owner.

Actually, and to their defense they do mention you - the buyer - might be of such high esteem. As a reverent plugin developer or a "high end mixer". whatever the fuck that means.

 

[rainton]

Actually, and to their defense they do mention you - the buyer - might be of such high esteem. As a reverent plugin developer or a "high end mixer". whatever the f**k that means.

Hahaaaa hilarious!! That's exactly what I thought!  ;D

 

[EEMO1]

Not sure if you guys are considering a very real alternative that this is a complete fake unit. It's not beyond the skill set of some people - like me for example (!!) -  to completely fabricate a "rare" unit like this including the serial stickers and wear. Elaborate background stories and small deviations like the mentioned mod or that "extra switch" are the hallmark of art forgery. Meant to distract the buyer from things that might be a bit off place. I'm surprised they didn't mention the usual Arabic/Chinese/Philippine prince etc. European royalty that was the previous owner.

Actually, and to their defense they do mention you - the buyer - might be of such high esteem. As a reverent plugin developer or a "high end mixer". whatever the f**k that means.

on the other hand, if you've ever seen something like pawn stars or some shit like that, people are totally delirious on the actual value of some stuff just because such-and-such has own/sat in it/used it/signed it...

 

[okgb]

Pawn stars ? Nothing is spontaneous on that show . I saw an episode where a local [ to my city ] antique dealer
brought on a piece and acted as joe citizen . When they bought and sold Mary Ford's Les Paul , turning it over for 30k
on ebay , I saw their feedback rating was quite high , don't know the ratio but internet seems to be substantial for them

 

[3nity]

Pawn shops in mtl are now buying pro audio stuff.
looks like gearsl**s is getting its toll.

 

[MatthewF]

Well, I've got no experience with either building or using an 1176, but this thread is too interesting to let slide so I'll have a pop! Looking at the schematic of the MC76 output amp (found on the last page of the manual: http://www.studiomanuals.com/docs/purple/PurpleMC76.pdf) I'll guess that it's related to the value of R29 and/or R30 i.e. the bias voltage at the base of the Darlington pair formed by Q5 and Q6? I can imagine that increasing this bias voltage would cause Q6 to run hotter...

Matthew

 

[frazzman]

It's much easier than that. -You're all over-thinking it.

Years ago I built a couple of 'bloo' clones, and they worked well... but they sounded unusually 'hairy'.

Here's the story: http://groupdiy.com/index.php?topic=38652.0

People liked the mod SO much that they really -REALLY- didn't want me to take them apart to see what was 'wrong' in case I 'fixed' the problem... So I built the third one, using -as far as I could remember- the same parts as the first two.

...and it DIDN'T have the 'funk'. -It was a proper, normal, fully-functioning 1176.

So I dug in with a scope, probed around, and after some head scratching I noticed that the class-A output stage was being differently-biased. -It wasn't running as efficiently as it should (not that it was ever very efficient!) and ran physically hotter, but in such a manner that the onset of distortion was actually rather pleasant... and-crucially- the RECOVERY from overload was also very nice.

-So I added a switch to the back panel, and sent it out for testing. -When Morrisound Studios down in Tampa had all of their outboard gear stolen (along with their SSL G-series power supply rack and computer, etc) I lent it -along with all of my other outboard gear- to them so they could continue working. -I told them about the switch, since they do a lot of rock work.

When I collected the units back from them several months later, it seems that they had just left it mostly in the 'hairy' position, and used it for the color.

I'll keep it to myself for now... but it's way easier than most of you are thinking. -I think that more people will LISTEN and UNDERSTAND if they try things for themselves... -if they just 'paint by numbers' the change, they don't really THINK or get deep into understanding how and why things work the way that they do.

But it was a single component swap. (And it had nothing to do with the 'wrong value resistor in the reissue' problem which John Hinson pointed out several years ago.)

I had almost exactly this same 'toggle switch on the back'...

(Or you could just have someone ask Chris Lord Alge.)

Keef

So Keith, after 3 years are you willing to share your wisdom with us on this mysterious mod ? I have a perfectly working rev A sitting here that it screaming to be tinkered with. Cheers!

 

[dreamix]

So what was this miswire? If black lion audio made clones of cla's bluey someone must have spotted it by now? Just curious after all these years what it was

 

[dreamix]

Ah well, lets find out this circuitry by taking it apart

 

[dreamix]

omg... this circuit is really messed up, it cant possibly be like the original, "exact replica of the original" ye right lol... I think I have to start a new thread about this schematic, there is added capacitors and resistors here and there inside the circuit. From pics of inside CLA´s bluey it looks like a "standard" rev B so Im not sure if it was added to make it sound more like the bluey, and the signal preamp section seems to tap signal out of the added SSL input circuit, so infact bypassing Q1... and yes I have a slight obsession solving this lol